Quartz (Milky and Smoky variety)

Physical Properties

Hardness: 7 on Mohs scale; Color: Milky white to grey/light blue; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & Geological History

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specimen likely originated in a pegmatite or hydrothermal vein system where crystals had space to grow before being encased or fractured.

Uses & Applications

Used in glassmaking, abrasives, electronics (piezoelectric properties), and as decorative garden stone or rough lapidary material.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but impurities or microscopic fluid inclusions create the milkiness seen here.

Field Identification & Locations

Identify by its ability to scratch glass and its lack of cleavage planes. Search in gravel pits, riverbeds, and mountainous regions with igneous or metamorphic outcrops.

Identified on: 4/19/2026

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